In the aircraft industry, where production rates are measured in the 10 to 25 aircraft per year range, the introduction of highly automated machines has been somewhat limited. Of course, the traditional computer controlled three and five axis milling machines have been used to machine large forgings, automatic fastener installation machines for wing and fusalage panels, etc. However, the use of robotic machines, such as spot welders found on automobile production lines, have not as yet found many economically viable applications.
With the introduction of the new generation of high power computers and their reduction in cost, it is now possible to use robotic type machines in the manufacture of low production rate articles such as aircraft.
Along with the new computers has been the emergence of composite materials as a viable aircraft structural material. Slowly over the years, composite structures have graduated from secondary structures such as fairings and radomes to vertical stabilizers, ailerons and flaps, etc. Now, composite wings and fuselage sections are a reality. The advantage of composites is that large and complex assemblies can be fabricated in what is almost a two-step process--layup of the uncured composite materials in a mold and the curing at high temperature under pressure. Composite materials produce a higher strength to weight ratio or modulus to weight ratio part at a lower cost.
However, such complex assemblies require considerable post processing. For example, composite fuselage section may require routing out of access holes, the drilling of fastener holes, etc. Furthermore, additional structural components must be installed therein. In the past, this was accomplished using conventional techniques during the final assembly parts. Unfortunately, for most robotic machines designed to accomplish a multitude of different functions, size is not necessarily basic consideration. Thus, with conventional robotic equipment there is often a problem of "reaching" into the interior of such a structure to accomplish even simple machining functions. For example, consider a six foot long fuselage section for a vehicle 30 inches in diameter and having interior bulkheads with only a 14 inch opening therein. The design of a computer controlled machine having a tool mount capable of shrinking down in size to fit through the 14 inch opening and thereafter radially expand and extend well into the interior of the structure to accurately perform such machining operations is not easy to accomplish.
Therefore it is a primary object of the subject invention to provide a multifunction machine too that can be used in confined spaces.
Another object of the subject invention is to provide a multifunction machine tool which has a three axis motion tool mount that could be used in confined spaces.
A still further object of the subject invention is to provide a multifunction machine tool having a rotatable and radially extendable tool mount located on an unsupported end of a horizontally translating beam wherein the static torque about the axis of rotation of the tool mount is counterbalanced.
A still further object of the subject invention is to provide a multifunction machine tool that has means to change the natural frequency of the tool mount positioning structure.